Chemistry 305 Laboratory Experiments Flashcards

Traditional vocabulary flashcards covering key terms, definitions, and concepts from the Chemistry 305 laboratory manual and appendices and exercises 1 through 12.

Density (Definition)

Physical property of a substance defined as mass per unit volume ($d = \frac{m}{v}$).

Meniscus

The curved surface formed by a liquid on the inside of a container like a graduated cylinder.

Precision

The degree of exactness of a measurement, often limited by the markings on the measuring instrument.

Accuracy

How close a measurement is to the true or accepted value.

Graduated Cylinder

A laboratory instrument used to measure liquid volume with a higher degree of accuracy than a beaker.

Volumetric Flask

A piece of glassware used to achieve the highest accuracy in volume measurements.

Alcohol Thermometer

Equipment used in the lab to measure the temperature of liquids, typically in degrees Celsius ($^{\circ}\text{C}$).

Analytical Balance

A high-precision instrument used to determine the mass of an object in grams.

Weighing by difference

A procedure where the mass of a substance is found by weighing a container with the substance and subtracting the mass of the empty container.

Density of Water (Standard Value)

Approximate physical property of water equal to $1.00\,g/mL$ at $4.0\,^{\circ}\text{C}$.

Specific Gravity

A unitless value determined by comparing the density of a substance to the density of water at the same temperature.

Hydrometer

An instrument placed in a liquid to determine its fluid density or specific gravity.

Urinometer

A small hydrometer specifically used in medical labs to determine the specific gravity of urine.

Physical Properties

Characteristics that describe a substance without causing change to its chemical composition, such as color, odor, and hardness.

Ductility

The physical property of a material that allows it to be drawn out into a thin wire.

Malleability

The physical property of a substance that allows it to be hammered or rolled into thin sheets.

Viscosity

A physical property of a fluid that describes its resistance to flow.

Standard Curve

A graph plotting generated data of known concentrations used to determine unknown concentrations through extrapolation.

Interpolation

The process of determining a value between known data points on a graph.

Extrapolation

The process of estimating an unknown value by extending a known sequence of values or a standard curve.

Line of Best Fit

A straight line drawn through various data points on a graph that gets as close as possible to as many points as possible.

Element Oxygen ($O_2$)

A colorless, odorless, diatomic gas that makes up about $21\%$ of the Earth's atmosphere.

Oxidation (Combustion)

A chemical property where oxygen reacts with other substances, often releasing energy in the form of heat.

Diatomic Element

An element that naturally exists as a molecule composed of two atoms, such as $O_2$ or $N_2$.

Catalyst

A substance that increases the rate of a chemical reaction without being used up itself.

Manganese (IV) oxide ($MnO_2$)

The black solid used as a catalyst to decompose hydrogen peroxide into water and oxygen.

Pneumatic Trough

A shallow pan used to collect gases over water by displacement.

Glowing Splint Test

A laboratory test for oxygen; a glowing piece of wood will reignite when inserted into a bottle of pure oxygen.

Sulfur Dioxide ($SO_2$)

The gas formed when sulfur burns in the presence of oxygen.

Iron (III) oxide ($Fe_2O_3$)

The product formed by the chemical reaction of iron (steel wool) and oxygen.

Magnesium Oxide ($MgO$)

The compound formed when magnesium metal is ignited and burned in the air.

Hydrates

Ionic salts crystallized in the presence of water that contain specific amounts of water molecules associated with the salt.

Anhydrous

A term describing a salt that has had its water of hydration removed, usually through heating.

Cobalt (II) chloride paper

A chemical test paper that turns pink in the presence of water and is blue when dry.

Magnesium sulfate heptahydrate ($MgSO_4 \cdot 7H_2O$)

The chemical name for the hydrate commonly known as Epsom salts.

Cupric sulfate pentahydrate ($CuSO_4 \cdot 5H_2O$)

A blue-colored hydrate that turns white or gray once fully dehydrated.

Plaster of Paris ($CaSO_4 \cdot \frac{1}{2}H_2O$)

Calcium sulfate hemihydrate, a common hydrate used in construction and medicine.

Theoretical percent water

The mass percent of water in a hydrate calculated based on its chemical formula ($\frac{\text{mass of water}}{\text{total mass of hydrate}} \times 100$).

Percent Yield

A measure of efficiency in an experiment calculated by ($\frac{\text{actual yield}}{\text{theoretical yield}} \times 100$).

Percent Error

A calculation of accuracy found by ($\frac{\text{actual value} - \text{theoretical value}}{\text{theoretical value}} \times 100$).

Crucible

A small porcelain container used to heat substances to very high temperatures.

Clay Triangle

Equipment used to support a crucible on a ring stand during heating over a Bunsen burner.

Lewis Dot Structure

A simplified representation of the valence electrons in a molecule used to show bonding between atoms.

Octet Rule

The tendency of atoms to prefer having eight electrons in their valence shell.

Charge Cloud (Electron Domain)

A region around a central atom containing a single, double, or triple bond, or a lone pair of electrons.

Lone Pair

A pair of nonbonding valence electrons on a central atom.

Molecular Geometry

The three-dimensional arrangement of atoms in a molecule.

Bent / Angular Geometry

The molecular geometry of a molecule like $H_2O$ or $H_2S$, which has two lone pairs on the central atom.

Electronegativity

A measure of the ability of an atom in a chemical compound to attract electrons.

Bond Polarity

A property of a chemical bond determined by the electronegativity difference between two bonded atoms.

Structural Isomers

Compounds that have the same molecular formula but different bonding arrangements or connectivities.

Precipitate

An insoluble solid material that forms in a solution during a chemical reaction.

Supernatant

The liquid solution that remains after a precipitate has formed and been filtered or settled.

Spectator Ions

Ions that remain dissolved in a solution and do not participate directly in a chemical reaction.

Buchner Funnel

A piece of laboratory equipment used for vacuum filtration of precipitates.

Vacuum Flask

A side-arm flask used in conjunction with a Buchner funnel and vacuum hose to speed up filtration.

Limiting Reagent

The reactant that is completely consumed first in a chemical reaction, determining the maximum amount of product formed.

Excess Reactant

The reactant that is left over after a chemical reaction has stopped because the limiting reagent is spent.

Double Displacement Reaction

An exchange reaction where the cations of two ionic compounds swap places in aqueous solution.

Driving Force

The factor that 'forces' a double displacement reaction to occur, such as the formation of a precipitate, gas, or water.

Total Ionic Equation (TIE)

A chemical equation showing all dissolved ionic compounds as individual cations and anions.

Net Ionic Equation (NIE)

A chemical equation that shows only the species directly involved in the chemical reaction, removing spectator ions.

Universal Gas Constant ($R$)

The proportionality constant in the Ideal Gas Law, often calculated as $0.08206\,L \cdot atm \cdot K^{-1} \cdot mol^{-1}$.

Ideal Gas Law

The mathematical relationship between pressure, volume, temperature, and number of moles of a gas ($PV = nRT$).

Eudiometer

A graduated gas collection tube used to measure the volume of gas produced in a chemical reaction.

Dalton’s Law of Partial Pressure

States that the total pressure of a gas mixture is equal to the sum of the partial pressures of the individual gases ($P_{\text{total}} = P_1 + P_2 + ...$).

Vapor Pressure of Water

The partial pressure exerted by water vapor in a closed container, which varies depending on temperature.

Standard Temperature and Pressure (STP)

Defined conditions of $273\,K$ (or $0\,^{\circ}\text{C}$) and $760\,torr$ (or $1\,atm$).

Molar Volume of an Ideal Gas at STP

The volume occupied by one mole of an ideal gas at STP, which is $22.414\,L/mol$.

Solvent

The substance in a solution present in the greater amount, often water.

Solute

The substance in a solution present in the smaller amount that is dissolved by the solvent.

Miscible

A term describing two liquids that dissolve completely in each other in any proportion.

Immiscible

A term describing two liquids, such as oil and water, that do not dissolve in each other.

Electrolyte

A substance that produces ions in water and can conduct an electrical current.

Strong Electrolyte

A substance that is $100\%$ dissociated into ions in water, such as $NaCl$ or $NaOH$.

Weak Electrolyte

A substance that is not fully dissociated in water and produces few ions, such as acetic acid ($HC_2H_3O_2$).

Non-electrolyte

A substance that dissolves in water as molecules and does not form ions, such as sugar or isopropyl alcohol.

Molarity ($M$)

A concentration unit defined as moles of solute per liter of solution ($M = \frac{\text{moles}}{\text{liter}}$).

Parts per million ($ppm$)

A concentration unit used for very dilute solutions, calculated as ($\frac{\text{grams of solute}}{\text{grams of solution}} \times 10^6$).

Equivalents per liter ($Eq/L$)

A concentration unit common in health sciences, based on the number of charges on dissolved ions.

Osmolarity

A concentration unit describing the total moles of all dissolved particles per liter of solution.

Intracellular Fluid

The aqueous solution found inside the cells of the body, where the major cation is potassium ($K^+$).

Extracellular Fluid

The fluid found outside the cells, where the major cation is sodium ($Na^+$).

Isotonic Solution

A solution with the same osmolarity as blood plasma, approximately $0.30\,osmol$.

Hypertonic Solution

A solution with a greater osmolarity than blood plasma, causing red blood cells to shrink due to water loss.

Hypotonic Solution

A solution with a lower osmolarity than blood plasma, causing red blood cells to swell and burst.

Osmosis

The process of solvent flowing through a semipermeable membrane from a region of low osmolarity to high osmolarity.

Parenteral Solution

A solution administered to the body by means other than the mouth, such as an IV bag.

Edema

A medical condition involving swelling in the tissues, often caused by high levels of $Na^+$ and $Cl^-$ ions.

Titration

A procedure where the volume of a reagent is measured as it reacts with a measured quantity of another reagent.

Neutralization

A double displacement reaction between an acid and a base that produces water and an ionic salt.

Endpoint

The point in a titration where the number of moles of base added equals the number of moles of acid, often shown by a color change.

Indicator

A special dye that changes color depending on the acidity or basicity of a solution.

Phenolphthalein

An organic indicator that is colorless in acid or neutral solutions but turns pink in basic solutions.

Buret

A precision glass tube used to deliver variable volumes of liquid during a titration.

Volumetric Pipet

A piece of glassware calibrated to deliver a single, precise volume of liquid when used with a suction bulb.

pH

The negative logarithm of the hydronium ion concentration ($pH = -\log[H^+]$).

Buffer

A solution of a weak acid and its conjugate base that resists changes in pH when small amounts of strong acid or base are added.

Buffer Capacity

The limit of a buffer's ability to maintain pH before being overwhelmed by added acid or base.

Anthocyanin

A natural acid-base indicator found in red cabbage that changes color across a range of pH values.